Innovations In Clinical Neuroscience

NOV-DEC 2017

A peer-reviewed, evidence-based journal for clinicians in the field of neuroscience

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64 ICNS INNOVATIONS IN CLINICAL NEUROSCIENCE November-December 2017 • Volume 14 • Number 11–12 O R I G I N A L R E S E A R C H structure in the network (i.e., it examines clusters of highly interacting symptoms). 18 As can be seen in Figure 1, the nodes (i.e., PANSS items) with the same color belong to one community and tend to have dense connections with each other and sparse connections with nodes of other colors (communities). Although the numbers of detected communities for the treatment-resistant and treatment-responsive groups were both 13 prior to treatment, the number of detected communities for the treatment-responsive group was lower than that for the treatment-resistant group after treatment (treatment resistant=11 and treatment responsive=12). Thus, mesoscopic level findings suggest that the symptom interaction network of the treatment-resistant group consists of less segregated communities after treatment as compared with that of the treatment-responsive group after treatment. Microscopic analysis. We conducted a microscopic analysis of symptom networks to understand the behavior of single nodes (PANSS items) in the network. Figure 2 shows the closeness and degree centrality network measures at baseline and the end of phase 1 for the treatment-resistant and treatment- responsive groups. As can be seen in Figure 2, symptoms close to the red line did not change their centralities much between before and after the treatment; in order words, they were not remarkably affected by the treatment (i.e., the network shape was consistent before and after the treatment). On the other hand, there were certain symptoms that were farther from the red line (e.g., "Blunted Affect," "Excitement," and "Preoccupation"), which means that these were the symptoms that received a great impact by the treatment. Moreover, for the treatment-responsive patients, there was a general trend of symptoms going up in centralities (i.e., the symptoms were lining up slightly above the red line), which means that the network became more connected after treatment. This was not observed in the treatment-resistant patients; their symptoms behaved almost randomly before and after treatment. Similarly, Figure 3 shows the network representation of closeness and degree centralities at baseline and the end of Phase I for the treatment-resistant and treatment- responsive groups. The node colors represent the difference of centralities between baseline and the end of Phase I. The negative values for node color reflect the decrease of centralities from baseline to the end of Phase I, while the positive values represent the increase of centralities from baseline to the end of Phase I. Moreover, the node size represents the absolute value of changes in centralities before and after treatment (baseline to the end of Phase I). As can be seen in Figure 3, the centrality values for certain symptoms markedly changed after treatment. More specifically, in the treatment-resistant group, "Preoccupation" and "Hallucinatory Behavior" demonstrated the most noticeable change in centrality values after treatment, while, in treatment- responsive patients, "Poor Rapport" had the most noticeable change in centrality values after treatment. The Kolmogorov-Smirnov test was used to examine the group differences of treatment- resistant and treatment-responsive groups in microscopic network properties. As can be seen in Table 3, there were no significant differences in the closeness and degree centrality of symptoms in the treatment- resistant group at baseline and at the end of TABLE 2. Macroscopic properties of partial correlation based PANSS networks MACROSCOPIC PROPERTIES TREATMENT-RESISTANT TREATMENT-RESPONSIVE BASELINE 18-MONTH FOLLOW-UP BASELINE 18-MONTHS FOLLOW-UP Density 0.15 0.15 0.13 0.14 Average clustering coefficient 0.06 0.06 0.04 0.05 Average shortest path length 10.11 10.25 13.18 12.32 Modularity 0.47 0.47 0.55 0.53 FIGURE 2. Microscopic analysis results. Clockwise from top-left: treatment-resistant/closeness centrality; treatment- resistant/degree centrality; treatment-responsive/degree centrality; and treatment-responsive/closeness centrality. The graphs represent closeness and degree centrality network measures at baseline and 18 months follow-up for treatment resistant and treatment responsive groups. The x-axis and y-axis show the centrality values at baseline and 18 months follow-up, respectively. pos _ p1 = Delusions; pos _ p2 = Conceptual Organization; pos _ p3 = Hallucinatory Behavior; pos _ p4 = Excitement; pos _ p5 = Grandiosity; pos _ p6 = Suspiciousness/Persecution; pos _ p7 = Hostility; neg _ n1 = Blunted Affect; neg _ n2 = Emotional Withdrawal; neg _ n3 = Poor Rapport; neg _ n4 = Passive/Apathetic Social Withdrawal; neg _ n5 = Difficulty in Abstract Thinking; neg _ n6 = Lack of Spontaneity and Flow of Conversation; neg _ n7 = Stereotyped Thinking; gps _ g1 = Somatic Concern; gps _ g2 = Anxiety; gps _ g3 = Guilt Feelings; gps _ g4 = Tension; gps _ g5 = Mannerisms and Posturing; gps _ g6 = Depression; gps _ g7 = Motor Retardation; gps _ g8 = Uncooperativeness; gps _ g9 = Unusual Thought Content; gps _ g10 = Disorientation; gps _ g11 = Poor Attention; gps _ g12 = Lack of Judgement and Insight; gps _ g13 = Disturbance of Volition; gps _ g14 = Poor Impulse Control; gps _ g15 = Preoccupation; gps _ g16 = Active Social Avoidance.

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